Medical device delivery system

ABSTRACT

A medical device delivery system comprises an inner tube, a medical device disposed about a portion of the distal region of the inner tube, a medical device sheath disposed about the medical device, a medical device sheath retraction device extending proximally from the medical device sheath and an outer sheath disposed about a portion of the medical device sheath retraction device. The distal end of the outer sheath terminates at least one medical device length proximal of the medical device. The medical device sheath is movable relative to the outer sheath and relative to the inner tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of Ser. No. 10/842,384,filed May 10, 2004, now U.S. Pat. No. 7,387,640, which is a ContinuationApplication of Ser. No. 09/681,157, filed Feb. 1, 2001, now U.S. Pat.No. 6,736,839, the contents of both of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

This invention relates to a medical device delivery system. The medicaldevice delivery system has a host of uses including as a stent deliverycatheter system, such as the kind used in percutaneous transluminalangioplasty (PTA) or percutaneous transluminal coronary angioplasty(PTCA) procedures. The delivery system employs a retractable sheathwhich exposes a medical device for deployment.

BACKGROUND OF INVENTION

In typical PTA or PTCA procedures, a guiding catheter is percutaneouslyintroduced into the cardiovascular system of a patient and advancedthrough the aorta until the distal end is in the desired artery orvessel. Using fluoroscopy, a guide wire is then advanced through theguiding catheter and across the site to be treated in the coronaryartery. A balloon catheter is advanced over the guide wire to thetreatment site. The balloon is then expanded to reopen the artery. Thecatheter may have a guide wire lumen which is as long as the catheter(over the wire) or it may be a rapid exchange catheter wherein the guidewire lumen is substantially shorter than the catheter. Alternatively, afixed wire balloon may be used. This device features a guide wire whichis affixed to the catheter and cannot be removed.

To help prevent arterial closure, repair dissection, or preventrestenosis, a physician can implant an intravascular prosthesis, or astent, for maintaining vascular patency inside an artery or other vesselat the lesion.

Stents are also used for a variety of other purposes includingmaintaining the patency of any physiological conduit including but notlimited to arteries, veins, vessels, the biliary tree, the urinarytract, the alimentary tract, the tracheobronchial tree, thegenitourinary system, and the cerebral aqueduct.

For the purposes of this disclosure stents and medical devices may beconsidered to include any stent, covered stent or prosthesis or anymedical device system, grafts or biologic device.

The stent may either be self-expanding or balloon expandable. For thelatter type, the stent is often delivered on a balloon and the balloonis used to expand the stent. The self-expanding stents may be made ofshape memory materials such as nitinol or constructed of regular metalsbut of a design which exhibits self expansion characteristics.

In certain known stent delivery catheters, a stent and an optionalballoon are positioned at the distal end of the catheter, around a corelumen. The stent and balloon are held down and covered by a sheath orsleeve. When the distal portion is in its desired location of thetargeted vessel the sheath or sleeve is retracted in a proximaldirection on the catheter to expose the stent. After the sheath isremoved, the stent is free to self-expand or be expanded with a balloon.

In a stent deployment system which utilizes a retractable sheath,retraction of the sheath may result in inaccurate placement of the stentfor a variety of reasons including, but not limited to, the interactionof the sheath and guide catheter upon retraction. One way of dealingwith this is to make the retractable sheath long enough so that it willbe contained in the guide catheter at all times. This increases systemprofile, reduces flexibility and creates excess friction upon sheathretraction.

Another way of dealing with this issues is described in commonlyassigned U.S. Pat. No. 5,772,669. The stent delivery system disclosedtherein comprises, in a catheter having a proximal outer shaft, aretractable distal sheath concentrically arranged around a stentreceiving portion of the catheter and a pull back means operativelyconnected to the distal sheath. The catheter is further arranged so thatthe retractable sheath or a member connected thereto is pulled into theproximal outer shaft of the catheter during retraction of the distalsheath thereby freeing the loaded stent.

All US patents and applications all other published documents mentionedanywhere in this application are incorporated herein by reference intheir entirety.

Without limiting the scope of the invention in any way, the invention isbriefly summarized in some of its aspects below.

SUMMARY OF INVENTION

In one embodiment, the invention is directed to a medical device orstent delivery system comprising an inner tube having a proximal regionand a distal region and a medical device or stent receiving region atthe distal end of the inner tube for receiving a medical device or stentthereabout. The system further comprises a medical device or stentsheath disposed about the medical device or stent receiving region. Themedical device or stent sheath is movable relative to the inner tube. Amedical device or stent sheath retraction device extends proximally fromthe medical device or stent sheath. An outer sheath is disposed aboutthe inner tube. The outer sheath has a proximal and a distal end, and isdisposed about a portion of the medical device or stent sheathretraction device. The distal end of the outer sheath terminatesproximal of the medical device or stent receiving region. The medicaldevice or stent sheath is movable relative to the outer sheath.

In another embodiment, the invention provides a stent delivery systemwhich comprises an inner tube with a stent disposed about a portion ofthe distal region of the inner tube and a stent sheath disposed aboutthe stent. The stent sheath is movable relative to the inner tube. Astent sheath retraction device extends proximally from the stent sheath.An outer sheath is disposed about a portion of the stent sheathretraction device. The outer sheath is characterized by a length whichdoes not exceed the difference in length between the inner tube andtwice the length of the stent. The outer sheath is located proximal tothe stent sheath. The stent sheath is movable relative to the outersheath.

In yet another embodiment, the invention provides a stent deliverysystem which comprises an inner tube with a stent disposed about aportion of the distal region of the inner tube, a stent sheath disposedabout the stent, a stent sheath retraction device extending proximallyfrom the stent sheath and an outer sheath disposed about a portion ofthe stent sheath retraction device. The outer sheath is characterized bya length which does not exceed the difference between the length of theinner tube and the length of the stent. The outer sheath is locatedproximal to the stent sheath. The stent sheath is movable relative tothe outer sheath and to the inner tube.

In yet another embodiment, the invention provides for a stent deliverysystem which comprises an inner tube with a stent disposed about aportion of the distal region of the inner tube, a stent sheath disposedabout the stent, a stent sheath retraction device extending proximallyfrom the stent sheath and an outer sheath disposed about a portion ofthe stent sheath retraction device. The outer sheath terminates at leastone stent length proximal of the stent. The stent sheath is movablerelative to the outer sheath and the inner tube.

Additional details and/or embodiments of the invention are discussedbelow.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a schematic side view of an embodiment of a stent deliverysystem according to the invention having a loaded stent including across-sectional view of the distal portion thereof and a side view ofthe proximal end of a stent delivery system according to the inventionshowing the manifold portion thereof.

FIG. 2 shows a transverse cross-sectional view of the stent deliverysystem of FIG. 1 taken along line 2-2.

FIG. 3 shows a transverse cross-sectional view of the stent deliverysystem of FIG. 1 taken along line 3-3.

FIG. 4 shows a schematic side cross-sectional view of the distal portionof a stent delivery system in accordance with one embodiment of theinvention.

FIG. 5 shows a transverse cross-sectional view of the stent deliverysystem of FIG. 4 taken along line 5-5.

FIG. 6 shows a schematic side cross-sectional view of the distal portionof a stent delivery system in accordance with one embodiment of theinvention.

FIG. 7 shows a transverse cross-sectional view of the stent deliverysystem of FIG. 6 taken along line 7-7.

FIG. 8 shows a schematic side cross-sectional view of the distal portionof a stent delivery system in accordance with one embodiment of theinvention.

FIG. 9 shows a side cross-sectional view of the distal portion of astent delivery system.

DETAILED DESCRIPTION

While this invention may be embodied in many different forms, there areshown in the drawings and described in detail herein specificembodiments of the invention. The present disclosure is anexemplification of the principles of the invention and is not intendedto limit the invention to the particular embodiments illustrated.

For the purposes of this disclosure, the term stent refers to stents,stent-grafts, grafts and other endoluminal prostheses whetherself-expanding, balloon expandable, self-expanding and balloonexpandable or otherwise expandable as are known in the art.

In one embodiment, the invention is directed to a stent delivery system,shown generally at 100 in FIG. 1. System 100 includes an inner tube 104with a proximal end 108 and a distal end 112. Distal end 112 terminatesin tip 120 which may be attached thereto or may be a part of the innertube itself Inner tube 104 may optionally have a guidewire 116 extendingtherethrough.

A medical device receiving region 124 is located at distal end 112 ofinner tube 104. As shown in FIG. 1, medical device receiving region is astent receiving region. Stent 128 is shown disposed about stentreceiving region 124.

Also disposed about stent receiving region 124 of inner tube 104 isstent sheath 132. Stent sheath 132 provides for a stent chamber 134 inwhich stent 128 resides. Stent sheath 132 has a hypotube 136 extendingproximally therefrom to the proximal end of the stent delivery system.Hypotube 136 serves as a stent sheath retraction device. Hypotube 136has an opening therein allowing for the delivery of a flush fluid tostent chamber 134. Hypotube 136 and stent sheath 132 may be formed ofone piece construction or may be joined together adhesively orotherwise.

Stent delivery system 100 further comprises an outer sheath 140 whichextends from the distal end of the stent delivery system. Outer sheath140 is disposed about a portion of inner tube 104 and a portion ofhypotube 136 and terminates proximal to stent sheath 132.

As shown in the embodiment of FIG. 1, distal end 144 of outer sheath 140is separated from proximal end of stent sheath 132 by at least thelength of the stent.

In use, the distal end of stent delivery system 100 is inserted in abodily vessel. Stent receiving region 124 with stent 128 receivedthereabout is advanced to a desired region in a vessel. Stent sheath 132is then retracted in a proximal direction by sliding hypotube 136proximally using slide 141 in manifold 143 so that the stent sheath nolonger covers the stent, thereby allowing for the deployment of thestent. Desirably, stent sheath 132 is retracted until it abuts distalend 144 of outer sheath 140.

For the sake of clarity, FIG. 2 shows the stent delivery system in atransverse cross-section taken through outer sheath 140 along line 2-2of FIG. 1 and FIG. 3 shows the stent delivery system in a transversecross-section taken distal to outer sheath 140 along line 3-3 of FIG. 1.

Stent 128 may self-expand upon retraction of the sheath or may beexpanded by the inflation of a balloon located underneath the stent (notshown in FIG. 1.). Thereafter, the stent delivery system is withdrawnwith the stent deployed in the desired location in the bodily vessel.

The embodiment of FIG. 4 is similar to that of FIG. 1 and furthercomprises a balloon 148 disposed about stent receiving region 124underneath stent 128. Balloon 148 is supplied with an inflation fluidvia inflation lumen 152 extending in inner tube 104. Although not shownin FIG. 2, the stent delivery system may further comprise a guidewire asis shown in FIG. 1. Other configurations of balloons and inflationlumens as are known in the art may also be employed.

For the sake of clarity, FIG. 5 shows the stent delivery system in atransverse cross-section taken through outer sheath 140 along line 5-5of FIG. 4. Note that in FIG. 5, guidewire 116, not present in FIG. 4, isshown.

In another embodiment of the invention, as shown in FIG. 6, a pull wire136 extending from stent sheath 132 serves as a retraction device ratherthan the hypotube shown in FIG. 1. Pull wire 136 is desirably connectedto pull collar 138 which, in turn, is connected to stent sheath 132. Inall other respects, stent delivery catheter 100 shown in FIG. 6 isidentical to that shown in FIG. 1.

FIG. 7 shows a transverse cross-sectional view of the stent deliverysystem of FIG. 6 taken along line 7-7.

In another embodiment of the invention shown in FIG. 8, stent deliverycatheter 100 includes a lengthier outer sheath 140 which extends tostent sheath 132 when stent sheath 132 covers stent 128. Stent sheath132 is retracted proximally by pulling on pull wire 136 which isattached by pull collar 138 to stent sheath 132.

In addition to the over-the-wire embodiments shown in FIGS. 1-8, theinventive stent delivery system may also be provided in a rapid-exchangeconfiguration. In the embodiment shown at 100 in FIG. 9 guidewire 116enters inner tube 104 through guidewire port 154 at distal end 144 ofouter sheath 140. Inner tube 104 extends from guidewire port 154 to tip120 of the stent delivery system 100. Guidewire 116 extends throughinner tube 104.

With the exception that the stent delivery system of FIG. 9 is arapid-exchange system and the stent delivery system of FIG. 1 is anover-the-wire system, the stent delivery system shown in FIG. 9 is usedin a manner identical to that of FIG. 1. Other details of rapid-exchangecatheters may be found in U.S. Pat. Nos. 5,534,007 and 5,833,706.

The inventive stent delivery systems may also be made in fixed wireform. The stent delivery system of FIG. 1, for example, may have a fixedwire extending from tip 120 rather than a removable guidewire.Additional details of fixed-wire catheters may be found in U.S. Pat. No.5,702,364.

More generally, the invention is directed to a medical device deliverysystem which comprises an inner tube having a medical device receivingregion at the distal end of the inner tube for receiving a medicaldevice thereabout and a medical device sheath disposed about the medicaldevice receiving region of the inner tube. A medical device sheathretraction device, for example, a pull wire or a hypotube, extendsproximally from the medical device sheath. An outer sheath is disposedabout a portion of the medical device sheath retraction device. Theouter sheath terminates proximal of the medical device receiving region.The medical device sheath is movable relative to the outer sheath and tothe inner tube.

The system may be adapted for use with a medical device such as a stent,for example, a self-expanding, balloon expandable or combinationself-expanding and balloon expandable stent. The system may also be usedfor delivery of other medical devices for use in the body as wellincluding, but not limited to, ultrasonic devices, laser devices, venacava filters, implantable drug delivery devices and the like.

Desirably, the outer sheath terminates at least one medical devicelength proximal of the medical device however other lengths can be used.In the case of a medical device only a portion of which must be exposedfor use in the body, the medical device length is considered to be thatportion of the device which must be exposed for use.

The medical device delivery system may be adapted for use in anover-the-wire configuration, in a rapid exchange configuration or fixedwire form.

The outer sheath of the medical device delivery system in general andstent delivery system in particular in its various embodiments may havea roughened surface to anchor the outer sheath in the vessel and tocounteract any retraction wire adjustments.

The stent delivery system may also comprise various coatings as areknown in the art, including lubricious coatings to facilitate movementof the various parts of the system. More information concerning suitablecoatings may be found in U.S. Pat. No. 5,443,907, and U.S. applicationSer. Nos. 08/382,478, 09/306,939 and 09/316,502.

An advantage of one embodiment of the medical device delivery systemdisclosed herein is the reduction in frictional forces on retraction ofthe medical device sheath. In at least some of the embodiments disclosedherein, the medical device sheath only encounters friction as it slidesover the medical device (for example, a stent). As soon as the medicaldevice has been cleared, the frictional forces associated withretraction of the medical device sheath disappear almost entirely as themedical device sheath does not contact the outer sheath. This allows forincreased accuracy in deployment of medical devices such as stents asthe jumping movement that typically occurs when deploying a stent with astent delivery system employing a full length sheath is substantiallyreduced. Other means by which this may reduce jump include but are notlimited to reduction of recoil of the catheter and reduction of kineticenergy.

In addition to its medical uses, the instant invention may also prove tobe of utility for non-medical uses as well. To that end, the inventionis also directed to a device delivery system comprising an inner tubehaving a proximal region and a distal region and a device receivingregion at the distal end of the inner tube for receiving a devicethereabout. The system further comprises a device sheath disposed aboutthe device receiving region. The device sheath is movable relative tothe inner tube. The system further comprises a device sheath retractionapparatus extending proximally from the device sheath. The outer sheathis disposed about the inner tube and about a portion of the devicesheath retraction apparatus. The distal end of the outer sheathterminates proximal of the device receiving region. The device sheath ismovable relative to the outer sheath.

It is contemplated that the invention may prove useful where it isdesirable to deliver a device to a location within a tube, pipe orconduit while protecting the device during delivery. Possibleapplications for the system include plumbing and electrical.

In addition to being directed to the specific combinations of featuresclaimed below, the invention is also directed to embodiments havingother combinations of the dependent features claimed below and thefeatures described above.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

The invention claimed is:
 1. A medical device delivery system fordelivering a medical device into a body lumen comprising: an inner tubedefining a guidewire lumen, the inner tube having a proximal region anda distal region and a medical device receiving region at the distal endof the inner tube for receiving a medical device thereabout; a medicaldevice sheath having a proximal end and a distal end, the medical devicesheath being disposable about the medical device receiving region andbeing movable relative to the inner tube; wherein the medical devicesheath has an outer surface that is free of any other structure of themedical device delivery system; a medical device sheath retractiondevice connected to the medical device sheath, the medical device sheathrefraction device being a tubular member extending proximally from themedical device sheath; an outer sheath disposed about the inner tube;wherein the inner tube, the outer sheath, and the guidewire lumen havesubstantially the same longitudinal axis; wherein the outer sheath hasan outer surface, a proximal end, a distal end, and a distal regionextending proximally from the distal end, wherein the distal region hasa constant outer diameter; wherein the outer surface of the outer sheathis free of any structure of the medical device delivery system adjacentthe distal end of the outer sheath; wherein the outer sheath is disposedabout a portion of the medical device sheath retraction device; whereinthe distal end of the outer sheath terminates proximal of the medicaldevice receiving region; wherein the tubular member and the inner tubeare not coaxial; and wherein the medical device sheath is movablerelative to the outer sheath.
 2. The medical device delivery system ofclaim 1, whereby the medical device sheath is moved proximally relativeto the inner tube and outer sheath to expose the medical device fordeployment, the medical device sheath extending distally from the outersheath.
 3. The medical device delivery system of claim 1, wherein themedical device is a stent.
 4. The medical device delivery system ofclaim 1, wherein the medical device sheath retraction device is ahypotube.
 5. The medical device delivery system of claim 1, wherein,when the medical device sheath is retracted, the outer sheath abuts themedical device sheath.
 6. The medical device delivery system of claim 1in over-the-wire form.
 7. The medical device delivery system of claim 1in rapid-exchange form.
 8. The medical device delivery system of claim1, wherein the medical device sheath has a first diameter and thetubular member has a second diameter, the first diameter being largerthan the second diameter.
 9. A medical device delivery system fordelivering a medical device into a body lumen comprising: an inner tubedefining a guidewire lumen, the inner tube having a proximal region anda distal region and a medical device receiving region at the distal endof the inner tube for receiving a medical device thereabout; a medicaldevice sheath having a proximal end and a distal end, the medical devicesheath being disposable about the medical device receiving region andmovable relative to the inner tube; a medical device sheath retractiondevice being connected to and extending proximally from the medicaldevice sheath; an outer sheath disposed about the inner tube; whereinthe medical device retraction device has a distal portion having anouter surface and wherein the outer sheath is the only portion of themedical device delivery system disposed about the outer surface; whereinthe inner tube, the outer sheath, and the guidewire lumen havesubstantially the same longitudinal axis; wherein the inner tube and themedical device retraction device are not coaxial; wherein the outersheath has an outer surface, a proximal end, a distal end, and a distalregion extending proximally from the distal end, wherein the distalregion has a constant outer diameter; wherein the outer surface of theouter sheath at the distal end of the outer sheath and along the distalregion defines an outer surface of the medical device delivery system;wherein the outer sheath is disposed about a portion of the medicaldevice sheath retraction device; wherein the distal end of the outersheath terminates proximal of the medical device receiving region whenthe outer sheath is fully extended distally relative to the inner tube;and wherein the medical device sheath is movable relative to the outersheath.
 10. The delivery system of claim 9, wherein the medical deviceis a stent.
 11. The delivery system of claim 9, wherein the medicaldevice retraction device is a tubular member.
 12. The delivery system ofclaim 11, wherein the tubular member is a hypotube.
 13. The deliverysystem of claim 11, wherein the medical device sheath and tubular memberare integrally formed.
 14. The delivery system of claim 9, whereby themedical device sheath is moved proximally relative to the inner tube andouter sheath to expose the medical device for deployment, the medicaldevice sheath extending distally from the outer sheath.
 15. The deliverysystem of claim 9 in over-the-wire form.
 16. The delivery system ofclaim 9 in rapid-exchange form.